


Just a Cat

by Scarpath



Category: Undertale (Video Game)
Genre: Cat Sans, Magic Illness, Other
Language: English
Status: In-Progress
Published: 2018-11-16
Updated: 2018-11-28
Packaged: 2019-08-24 09:43:14
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,949
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16637531
Author URL: https://archiveofourown.org/users/Scarpath/pseuds/Scarpath
Summary: Red finds a small cat near death from dehydration. Turns out, the cat isn't quite what he thought it was.





	1. Chapter 1

Sans opened his eyes slightly when he heard footsteps. It was the steps of another skeleton- well, not another. Sans wasn’t a skeleton anymore, hadn’t been since the ‘accident’.

 

The skeleton stopped right in front of Sans. It made him nervous, especially seeing how... rough the guy looked. Sharp teeth (Was one of them  _ golden? _ ) a crack through the socket, and dark clothing. Would he hurt Sans?

 

It wasn’t like there was anything he could do about it, though. He was so tired, so hungry. He was damn near dead, and completely at this stranger’s mercy. Sans made a small noise, one that seemed to garner him some sympathy.

 

“Hey there little guy. I ain’t gonna hurt’cha.” The skeleton’s deep voice soothed Sans somewhat. Even when the skeleton knelt to pick him up, he just gave a tired little ‘murr’.

 

Soon he was being held close to a soft sweater. A hesitant purr rumbled from him when he felt gentle claws scratching behind his ears. “Let’s you to a vet, little guy. Yer too skinny. ‘Sides, I can have ‘em check for a chip. You just hang in there, little fella.”

 

Sans could tell that the monster was probably only talking so much because he could tell his voice was soothing Sans. Still, it was appreciated. He found himself lost in thought, with the voice proving great at keeping him calm.

 

He had been pretty lucky, all things considered. He was more than willing to forget his initial fear of the skeleton holding him considering the guy was taking him to a vet instead of a shelter. Sans had avoided getting caught for so long out of fear of going to a shelter and never being adopted. He knew what happened to cats that didn’t get adopted.

 

But he wasn’t being taken to a shelter. He was being taken to the  _ vet _ , which meant the skeleton was possibly considering keeping Sans. It would be a little degrading to just be someone’s pet, but it was probably better than living out on the streets like he had been. He had run himself ragged, eaten trash, and overall suffered on the streets. He was lucky that it was a monster who found him, instead of a dog or something else that would just finish him off. He hadn’t found even any garbage to feed on lately. He wouldn’t have been able to run away fast enough.

 

Sans broke out of his thoughts when he noticed the sign of a veterinary hospital. Stars, there had been one so near? Not like he could have just sauntered in and expected any care without a monster or human paying for it, but still. At least he was here now.

 

He didn’t pay all too much attention to the words of his savior or the receptionist, though he did pick up the name of the skeleton. Red. A bit odd of a name, but it fit with Red’s magic and clothing choice. There were worse things to be named after than a color.

 

Sans was taken back to an exam room, and thankfully Red had been allowed back with him. Red was only more familiar to him by a few minutes, but Sans wasn’t going to turn down anything he could get. He patiently sat through the exams, not wanting to give any trouble. He hardly flinched when he felt a prick on one of his forearms(forelegs, he’s a cat now. Cats don’t have arms.). He needed the fluids pretty bad, so he just sat through the uncomfortable feeling of too-cold liquid flowing into him.

 

The anti-flea stuff smelt awful, but stars if he didn’t appreciate it. The bugs left him itching like mad. The mush he was given tasted pretty bad, but that was probably because medicine was mixed in it. He choked it down.

 

Then Red agreed to have them watch Sans overnight to make sure he was recovering well. Sans felt a good dose of panic, but he shoved it down. Red had saved him, Sans refused to repay him by being difficult. He just gave a single mournful meow as he was locked in a cage and Red was walking away.

 

Red froze, and shot Sans a look. He sighed, striding over to the cage. “It’ll be okay, little guy. I’ll be back for ya tomorrow. Got a bit of a soft spot fer little furballs like you. I’ll have some nice food and toys waiting for you.”

 

Sans gave a small, happy ‘murr’, nuzzling into Red’s fingers when they were offered. His small purr didn’t fade until well after Red was out of sight. Sans may be little more than a pet now, but he could still respect a good guy like Red.

 

The soft blanket he was placed on did little to pad the unforgiving metal bottom of the cage, but it was worlds better than what Sans had been sleeping on recently.  He was able to get some good sleep, only waking when a new bag of fluids was attached to his IV. He nuzzled into the blankets, finding warmth to ward off the lukewarm liquid born chill.

 

He was more than happy to see that Red was already there when he woke up. “Hey there, little guy. Doc’s gonna take out the IV, then we can get ya to yer new home.”

 

It didn’t take more than a moment for the IV to get removed, and Sans was sent off warm in Red’s arms. They’d only been walking about a block when Red paused. Sans couldn’t quite place the look directed at him. “Hope you don’t mind a little detour. I’m probably wrong, but I’ve got a sinkin’ suspicion and I need ta be sure.”

 

Sans, of course, didn’t mind a detour. He was happy in Red’s arms. His visit to the vet left him feeling worlds better, and he only got the undoubtedly expensive trip because of Red.  They walked a ways, and entered a pretty nondescript building. Sans was shocked to realize it was a laboratory not too unlike the one he worked in prior to being catified.

 

They walked into a personal lab, marked as belonging to one Red Gaster. Sans wasn’t too thrilled to be back in the lab, not after his last time in one.

 

Even so, Sans didn’t put up a fuss. He didn’t want to believe that the kind monster who’d shown him such compassion would hurt him. Red took a small blood sample, and seemed to be careful not to take more than he had to. Sans was still fairly dehydrated.

 

Sans just layed down on the table, watching Red bustle around the lab with the precious sample. After a while, a piece of paper was printed out. Seeing how nervous Red was to actually pick up the paper, Sans figured it would reveal whatever Red was looking for. Red closed his eyes, mumbling to himself. “Cat’s can have magic. Sure the little guy has more magic than any normal cat, but that doesn’t mean he’s...”

 

Sans’ ear twitched. Did Red somehow know? Sans could only hope. It would be nice living with someone who knew he was more than just a cat.

 

Red picked up the paper. He read it almost frantically, and slumped when he saw the results. He walked over to the table Sans was laying on, pulling up a stool. He set the paper where Sans could see it. He pointed out a few lines on it and started to speak. “Felt that you had a lot of magic. More than a cat normally would. Had ta be sure. But this line shows Monster DNA, with that of a cat superimposed onta it. This identifies the magic with that of a skeleton. A couple other things here also point that yer not supposed ta be a cat.”

 

Red sighed, covering his eyes with a hand. Sans gave a small meow, moving the paper closer to him with a paw. He read over it, wondering what else it showed. The results looked so specific, not like the more standardized test Sans thought Red might have used. It showed a lot of things pertaining to Sans’ health, sure, but most of the things it was looking for seemed to be relevant to how Sans was physically in terms of the change. He felt a little nauseous at the implications.

 

He looked back to Red, who seemed unable to meet his gaze. “I’m sorry. This is my fault. I’d been trying to see if changing a monster to a more physical form could help ward off some soul related illnesses. I scrapped the research, since I couldn’t manage much more than to turn a monster into a smaller animal. We had a major security breach a few months ago, and they managed to make copies of a lot of our research. I’m really sorry my work was used against you.”

 

Oh.

 

Sans reeled a little at the information. It made all too much sense, though. The guy who’d fed Sans the stuff that changed him wasn’t all that good at research, and Sans had been pretty suspicious of him. He’d confronted him about it, then foolishly accepted the peace offering when they had another meeting about Sans’ suspicions. Hearing that the knowledge to change him had been stolen only confirmed what Sans already knew- the guy was a thief who would go to any length to hide the fact.

 

Sans was broken out of his thoughts when a drop landed on the table. He looked up to see that Red was actually crying over the knowledge that his work had been used to hurt instead of help. There was too much honesty in those tears, and Sans felt confident that Red hadn’t meant for his work to be used like this. It wasn’t Red’s fault.

 

Sans couldn’t speak in anything but meows, so he resolved to get his message across some other way. He forced a purr and moved closer to Red. He used his paw to wipe at Red’s tears.  _ ‘It’s okay. I don’t blame you.’ _

 

“Yer not upset?” Red looked at Sans with such hope in his eyes. It broke his heart just a little. Red was so ready for Sans to hate him, even when it wasn’t really his fault. Sans gave a decisive meow, and licked at the bridge of Red’s nose. It drew a small laugh from Red. 

 

“I’ll do my best ta make it up to ya. It might take me awhile, but I’ll see if I can’t figure out how ta reverse it.” Sans froze at that. After a moment, he shook his head.

 

As spiteful as the application was, Red’s research had managed in a backwards way to do exactly what it was supposed to. Help someone with a sickness of the soul. Sans moved back over to the paper, scanning it for a way to communicate that. He dug a claw to make a few small cuts next to the important lines. He then pushed the paper over to Red.

 

It took Red a long moment to figure it out, but he gave Sans a sad look when he put it together. “Rickson’s Syndrome?”

 

Sans nodded. Rickson’s Syndrome, named after the physician who first documented it, occurred when the soul didn’t properly communicate with the body. In humans it wasn’t too bad, but with monsters it was almost always fatal. Magic came from the soul, and a monster’s body was made mostly of magic. Sans had a fairly minor case of it, allowing him to survive childhood unlike most with the syndrome. However, it still had taken its toll on Sans. He managed to function, sure, but it had been getting worse and worse as time went on.

 

Before he was changed to a cat, he had already been confined to a wheelchair for around three years. He had been blind in his right eye, and his right hand had completely dusted away. His left foot also dusted after he had fallen over. What would have just given a normal person a sprained ankle had completely destroyed his foot and nearly killed him as the dust hadn’t stopped spreading. He’d only had a stump of a leg by the end of the hospital visit.

 

As a cat though, the injuries hadn’t carried. He was whole again, and able to do so much  _ more _ . He even had a whole fifteen hp!

 

It was a bit annoying at times, sure. However, a lot of that was because he had no place to call home. So long as Red really took him in, then Sans was honestly at peace. Well, maybe he could figure out a way to communicate to Red who had turned him, and get the guy locked up. Then he’d be happy.

 

Sans lept from the table onto Red’s shoulder. It seemed to take Red somewhat aback, but earned him a laugh. “Okay, okay. Let’s get ya home. I’ll see about getten somethin’ you can use to talk with me a little better, and we can go from there. If you’ve got family, I’m sure they’ll be happy to know yer okay.”

 

That drew a pretty loud meow from Sans. Stars, Papyrus was probably so worried, if he didn’t already think Sans had passed away. “Okay, that’ll be the first thing we do then. My tablet might work.”

 

Sans rode on Red’s shoulder as he walked, drawing a few funny looks from passer-by. It must have been an amusing sight for sure, a rough looking guy like Red with a small white cat perched on him. Indeed, for all Red looked, he was a huge softey.


	2. Chapter 2

**Notes for the Chapter:**

> My tumblr: https://www.tumblr.com/blog/scarpathwrites
> 
> So... a lot of people like this fic. Thank you for all the support, guys!

After they got home, they learned that Red’s tablet worked just fine for Sans. Sans had opened up the email, figuring it to be the best way to contact Papyrus like this. He spent a good long time typing, having to go painstakingly slow trying to type with a paw instead of a finger. Eventually though, he was able to hit the send button. Now to hope Papyrus believed him and actually came to visit Red like he’d asked.

 

Sans then spent a while just talking with Red through the keyboard, telling him a little about himself. They also started discussing how they’d handle the person who turned Sans to a cat in the first place. After a point, Sans mentioned that they should continue the conversation when Papyrus came over.

 

Red teasingly downloaded one of those apps meant to entertain cats. Sans gave him a long look, then pointedly swatted at one of the fish that was swimming across the screen. Red had a good laugh at Sans actually playing around with the app. So what if he found enjoyment in cat things? He was a cat! A skeleton turned cat, but still a cat!

 

He was quick to leave the app when he saw the notification for an email. Fun app or not, Papyrus was the most important person to Sans. The responding message was simple, but still set a purr rumbling in Sans’ throat.  _ ‘Be there in ten.’ _

 

He caught Red’s attention, pointing out the message. Red smiled, giving Sans a two fingered noogie. Sans batted at his hand for the trouble. “I’ll go get started on dinner. My own brother should be home before too long.”

 

Sans turned his attention back to the tablet after Red left. He doubted that Papyrus would send any more emails, but he didn’t want to miss it on the off chance he did. He decided to just open up Youtube and watch a random ten-minute video.

 

When he heard a knock on the door, Sans rushed over. The instant Red opened it, Sans darted out to wind around Papyrus’ legs. “Paps I’m so happy to see you! Paaappsss.”

 

Of course, all that came out was a litany of meows, but surely the thought counted.

 

Tears welled in Papyrus’ eyes. He bent down so he could tenderly pick Sans up. “I’m so glad to see you, Sans.”

 

“Aw man, don’t cry bro.” Sans reached up with a paw, wiping at Papyrus’ tears.

 

“How about you come inside.” Papyrus took Red’s gentle offer, closing the door behind him. He sat on the couch at Red’s behest.

 

Papyrus held Sans awkwardly in his lap, and so, as a true cat would, Sans nuzzled his face against Papyrus’ hands. It drew a watery chuckle from him, so Sans figured it was at least a little better than before.

 

Sans hopped off Papyrus’ lap for the moment, mostly so he could push the tablet closer. When Papyrus picked it up and put it on the couch next to him, Sans gave a little meow of thanks. He started typing, occasionally having to press a letter a couple times as it struggled to pick up on all his little taps. Typing was a nightmare, but it was Sans’ best mode of communication.

 

_ ‘Im okay bro. Rly. Its a bit od but im still here. Red thinks ill hve a norml monster lifespan even.’ _

 

“Your typing skills have only gotten worse, brother.” Papyrus’ statement earned him a swat with a paw. The little Nyeh proved it was just a tease. He sobered up a moment later, gazing again at the message Sans had typed. 

 

“I am glad you are alright. Different, and now an animal I am allergic to, but alright.” Sans purred quietly, nuzzling against Papyrus’ hand before turning back to the tablet.

 

_ ‘On the bright sde ill lve lnger thn a year’ _

 

Papyrus gave a choked sob, and Sans knew he needed it. He gave support the best he could, purring and encouraging Papyrus to pet him.

 

“Are you still in pain? Or was that fixed alongside your missing limbs? And can you see out of both eyes again?” Sans gave a chirping meow at the question, turning back to the tablet.

 

_ ‘No more pain. I wrks agin. Im healther thn ever.’ _

 

Red had indirectly given Sans everything Papyrus had tried to give. He’d have a lot to adjust to, sure, but his quality of life... He’d be able to  _ live _ . He could run, he could see from both eyes, his body would no longer try to rob him of happiness.

 

When Red came back from the kitchen, where he’d gone back to cooking to give the brothers some privacy, Papyrus stood to give him a tight hug. “Thank you so much, Red. This isn’t a cure, but it’s still more than we dared hope for. Th-”

 

Papyrus broke the hug to sneeze into his shoulder. “A-ah sorry about that. I’m... allergic to cats.”

 

“Oh.” Red gave Papyrus an apologetic look. “That might make things interesting. If it helps, Sans will always be welcome here, as will you.”

 

A couple tears welled in Papyrus’ eyes, and he wasn’t sure if it was the allergies or just how grateful he was. He gave a small bow, if just to get across his pure gratitude. “Thank you so much. Sans is my whole world, and knowing he’ll be able to celebrate many more years of life without his illness causing him more pain means everything to me. You saved his life, directly and indirectly. I-”

 

Papyrus was broken off by a long string of sneezes. He wiped the tears away from his heated sockets. Red put a hand on his arm. “Bless you! And please, this is the least I can do to make up for letting my research find its way to the wrong hands. This may be a happier ending than it might have been, but that doesn’t make up for the fact that it was used as a weapon against Sans.”

 

Sans gave a scolding meow, giving Red’s leg a small swat as if to tell him not to be upset. Red picked him up in response, holding him close to his chest. Sans settled down, making a mental note to chew Red out later.

 

“Even so, thanks to your research Sans will be able to live a much longer life. We- Sans surpassed all doctor estimates living as long as he has. Even so, we didn’t expect to have him much longer than a year from now. And that was only if he managed to avoid any injuries. Even something as little as a sprained ankle nearly killed him once before, and he only got weaker. Thanks to you, I’ll have my little brother for years yet.” Tears flowed freely down his face, and his words were punctuated by sneezing. Still, Papyrus had a large smile.

 

The genuine gratitude drew a few tears of his own from Red. He had written off the research, not thinking anyone would wish to be turned to something like a cat, even to save their life. He was forced to reconsider it as he saw the heartfelt appreciation from Sans and Papyrus.

 

He gently smoothed the fur on the top of Sans’ head with a small smile. “I’m glad that I’ve made such a difference. That my work helped. I’d be honored to look after you if you want to stay with me, Sans.”

 

Sans didn’t hesitate to nod. He’d prefer to stay with Papyrus, but it just wouldn’t be possible. His older brother had a fairly severe allergy, and didn’t respond well enough to medications for it to be a long term solution. Red was a good monster, though, and Sans felt safe with him. Besides, it’d be a shame to waste the toys Red had so generously gotten him before even knowing for sure he was once a monster.

 

Papyrus sighed after yet another bout of sneezing. “As much as I would love to spend more time with Sans, I think it would be best if I head out soon. I will get some better allergy medicine so my next visit doesn’t have to be so short.”

 

Sans wiggled out of Red’s hold at that, moving so he could type a quick good-bye.  _ ‘Bye, bro. Love you!’ _

 

Papyrus smiled, moving to kiss Sans on the top of his head. He wouldn’t let his allergy keep him from giving the ritual kiss. “I love you too, Sans. Be good for Red.”

 

Red made his way back from the kitchen, having packed a small dish quickly. “Here, since Sans mentioned you work nights. It’s my own brother’s favorite. You can just bring back the dish when you visit next.”

 

Papyrus took the food gratefully. “Thank you. I’ll let you know when I plan to come next.”

 

When the door clicked shut behind Papyrus, Sans’ tail drooped. Papyrus had been taking care of him for so long.

 

When their parents learned of his disability, and couldn’t afford to raise him anymore, and Papyrus had insisted that they couldn’t be separated. When one of their foster families threatened Sans’ life if Papyrus didn’t behave perfectly, saying they could make it look like an accident easily. When they were never adopted, and Papyrus had to get a job as quickly as possible so he could adopt Sans himself and get him away from yet another bad foster family.

 

Life had always been awful for Sans, but Papyrus was always there for him. He’d made live livable for Sans. And now they couldn’t even be around each other without Papyrus getting attacked by allergies.

 

The small cat hopped up onto the couch, laying down with a defeated air. Red sat next to him, gently stroking his fur. “Seems like you two are really close... it’ll be okay, sweetheart.”

 

Sans just gave a sad meow, leaning against Red’s leg. He already missed his brother.


End file.
